1. Field of the Invention
The present invention relates generally to a folder-typed mobile wireless terminal with a built-in antenna in a main body thereof, and more particularly, to a device and method for improving a radiation pattern of a built-in antenna in a mobile wireless terminal, in which the built-in antenna is designed to have a constant radiation pattern and gain, regardless of whether a folder of the terminal is opened or closed.
2. Background of the Invention
Recently, a mobile wireless terminal such as a Personal Communication System (PCS), Digital Cellular System (DCS), Global Positioning System (GPS), Personal Digital Assistant (PDA), cellular phone, or wireless notebook has become popularized, and terminals with various functions and designs have been introduced. Further, small-sized, slim, and lightweight terminals have been introduced. Additionally, these terminals are required to have various functions. Therefore, the design of the terminal is focused on volume reduction while maintaining or improving the functions, for a customer satisfaction.
More specifically, a rod antenna (or whip antenna) or a helical antenna that is protruded outward from the terminal is easy to break when the terminal is dropped, and the antenna lowers the mobility of the terminal. Therefore, a plate-type antenna installed within the terminal, i.e., a built-in antenna, internal antenna, or intenna, is now used and various efforts are made to improve the performance and productivity of the built-in antenna.
Generally, the built-in antenna is electrically connected to a radio frequency (RF) board of a terminal main body by connecting directly or using a cable, such as a flexible printed circuit (FPC), to space the antenna away from the RF board. When the built-in antenna is directly connected to the RF board, the built-in antenna is connected to ground means such as a pin connector that is protruded upward from the RF board of the terminal main body.
However, when calling with a folder-typed wireless terminal, a folder (sub-body) should be opened at a predetermined angle from the terminal main body. As a result, the folder-typed mobile wireless terminal with a built-in antenna has a disadvantage of deteriorating call quality and lowering reliability because a radiation pattern of the antenna becomes different according to an opening and closing of the folder of the terminal. An attempt to avoid spurious occurrence and radiation has been made by entirely or partially spraying a conductive material inside of a frame of the terminal. However, there is still a problem in that the opening and closing of the terminal influences the radiation pattern of the built-in antenna of the terminal.